A power unit is known that is provided with a torque damper for absorbing excessive torque occurring in a power transmission path between a drive rotating shaft and a driven rotating shaft. The torque damper includes an input member adapted to receive torque from the drive rotating shaft and an output member transmitting torque transmitted from the input member to the driven rotating shaft and absorbing excessive torque by relative rotation between the input member and output member. See, for example, Japanese Patent Laid-open No. Sho 58-191680.
In addition, a vehicle power unit is known that is provided with an internal combustion engine and with a transmission that is composed of a swash plate type hydrostatic continuously variable transmission. See, for example, Japanese Patent Laid-open No. 2005-248838 and Japanese Patent Laid-open No. 2005-263143.
In a power unit including a torque damper mounted to a drive rotating shaft (a driven rotating shaft) rotatably supported by a pair of bearings, the torque damper and an output rotating body (or an input rotating body rotatably driven by a drive rotating shaft) rotatably driving a driven rotating shaft may be disposed so as to put one of the pair of bearings therebetween in the axial direction of the driving rotating shaft (or the driven rotating shaft). In such a case, since the whole of the torque damper is disposed between the pair of bearings, the length of the driving rotating shaft (or the driven rotating shaft) between the pair of bearings is increased. This needs to increase the length of the rotating shaft and the rigidity of the rotating shaft to suppress the occurrence of bending deformation of the rotating shaft due to the provision of the torque damper. Consequently, the weight of the rotating shaft may increase.
If, to position one of the pair of bearings, the driving rotating shaft (or the driven rotating shaft) is integrally formed with a positioning portion or a dedicated positioning member is used, the costs are increased.